Description: TERRANEX SF – 21 is solvent free low viscosity two component epoxy primer product based on epoxy (resin) and reactor (hardener) to be used with self smoothing epoxy and PU scratch coat for binding with floor system or other cementitious substrates where surfaces are very porous, it required more than one coat of primer to achieve the desired bonding efficiency. If the substrates are particularly smooth the surface of the TERRANEX SF – 21 should be seeded with fine aggregate immediately after application of the primer to give a mechanical key to facilitate installation of resin screed and topping.